In a flow meter that uses a thermal type flow rate sensor, it has been proposed to increase the detection sensitivity thereof, to compartmentalize the interior of a flow path having a flow rate sensor attached to a wall surface thereof to detect minute flow rates into a plurality of flow paths along the direction of fluid flow so as to increase the flow velocity at the aforementioned wall surface location, and to provide a nozzle at an intermediate location on that flow path so as to increase the flow velocity at the nozzle (see Japanese Unexamined Patent Application Publication No. 4-69521 and Japanese Unexamined Patent Application Publication No. 11-173896, for example).